eppand

This plugin will add a configurable widget to display social media icons in your widget area(s). Icons are 32×32, squared edges, and display inline.
Supported social media links include:
<ul>
<li>Twitter</li>
<li>Facebook</li>
<li>Google+</li>
<li>LinkedIn</li>
<li>YouTube</li>
<li>Pinterest</li>
<li>RSS</li>
</ul>
Available Languages
<ul>
<li>English (en_US)</li>
<li>Serbo-Croatian (sr_RS) – Borisa Djuraskovic at (http://www.webhostinghub.com/)</li>
</ul>
UPGRADE NOTICE
A change has been made to the social profile links if you are upgrading this plugin from a version prior to 1.0. The Social Media URLs are managed from a new area in the WordPress admin and will require you to enter your URLs again.

SimpleConnectWidget

This plugin will add a configurable widget to display social media icons in your widget area(s). Icons are 32x32, squared edges, and display inline.

Louy Alakkad

GeePress, gives you all the tools you need to integrate your WordPress and Google+, including “Login with Google+” and “Comment via Google+”… Highly customizable and easy to use.
<h4>Key Features</h4>
<ul>
<li>Allow your visitors to comment using their Google+ accounts</li>
<li>Allow your blog users to sign in with their Google+ accounts. one click signin!</li>
<li>Easily customizable by theme authors.</li>
</ul>

GP – GeePress

All the tools you need to integrate your WordPress and Google+.

SimpleConnectWidget vs GP – GeePress